1. Field of the Invention
The present invention relates to an electric pump driven by an electric motor.
2. Description of the Related Art
Among measures to improve automobile fuel efficiency are firstly idling stop adapted to stop an engine when a vehicle stops, and secondly hybridization adapted to drive a vehicle using a rotary electric machine and an engine. These measures have already found commercial use. To use these systems, a drive source is additionally required for a pump in the case of an idling stop system because the engine stops when the vehicle stops. In the case of hybrid vehicles, on the other hand, a water pump is required to cool the drive motor or starter-generator and its controller in addition to the idling stop system. As a result, an electric pump using an electric motor is increasingly common as a drive source.
JP-A-2000-213490 discloses an electric motor adapted to discharge cooling water by use of centrifugal force generated by rotating the impeller with the output shaft of the electric motor.